The United Nations says there are reports showing the government of Myanmar has been involved in recent deadly violence against Rohingya Muslims.

On Thursday, the UN special rapporteur on Myanmar human rights Tomas Ojea Quintana issued a statement saying that “I have received reports of State involvement in some of the acts of violence.”

“The military and police must now be held to account for human rights violations,” he added.

At least 40 people have been killed in central Myanmar after a fresh wave of attacks against Muslims broke out on March 20, prompting government officials to impose emergency rule and curfews in several areas.

Quintana went on to say that the government should take “immediate action to stop the violence from spreading to other parts of the country and undermining the reform process.”

The new escalation of violence against the country’s Muslim population saw mosques burned, houses razed and charred bodies left lying in the streets, in what many witnesses described to a large extent as part of a well-organized campaign.

Vijay Nambiar, the UN’s top adviser on Myanmar who toured the violence-hit town of Meiktila on Sunday, agreed that “much of this violence was planned” and called on the government to punish those responsible for the tragedy.

Myanmar’s government has been repeatedly criticized for failing to protect the country’s Muslim community, known as Rohingyas.

Hundreds of Rohingyas are believed to have been killed and thousands of others displaced in attacks by Buddhist extremists, who frequently attack the Muslim community and burn their homes in the state of Rakhine.